Heat dissipating structures have long been included in a variety of integrated circuit (IC) devices. Typical heat dissipating structures can be found in heat spreaders, cooling plates, Peltier devices, thermal adhesives, bonding over active circuits (BOAC) and use of varying structural materials in an effort to absorb and/or dissipate heat. In certain high power applications, an increase in temperature can adversely affect reliable device functioning.
For example, high power semiconductor devices experience transient periods immediately after input power is turned on or off. During these periods, high current and voltage spikes are present, resulting in peak power for the device. Such voltage spikes are particularly evident in power electronic integrated circuits (ICs), where power FETs constitute a large percentage of the die area. When excessive power is dissipated within a junction, its temperature rises. By way of example, a pulse period in a laterally diffused metal oxide semiconductor (LDMOS) device is 1-3 ms, and a temperature rise during that interval can be several hundred degrees. This temperature rise can limit the amount of power that can be handled by the device in any given cycle, which can be unsuitable for some high power applications. As junction temperature rises beyond a critical limit, the device can suffer reduced operating capability or irreversible damage.